I had this all typed up once and my damned browser crashed.

Mods:  Please delete the tacked "teaser" thread and tack this one instead.   Thanks.

With apologies for how long this took, I'm pleased to present the home hot bluing howto guide.    This will start off you brave souls who are looking for a real nitrate blue on pistol sized jobs at home.   I even screwed up my project yesterday so you'll get a nice example of what NOT to do as well.

I'm not going to get into the metal working, as that's a topic in and of itself.  But, I hope this will be informative and helpful.

Lets get started, shall we:

SUPPLIES
=======

Buy, borrow, beg, requisition or or otherwise obtain the following:


Equipment & Containers

*  Hotplate or other heat source that will provide reliable stable 300+ degree heat.

*  Good thermometer

*  Stainless Tongs.

*  Steel or UNTREATED wood stirring rod.

*  Brownells Black Iron Quarter Tank.  Link

* 3 or 4 Pyrex Glass Casserole Pans

*  At least 3 Stainless Steel pans for boiling TSP cleaning, pre-heating, and for after salts rinse.

*  Spray Bottle with mist nozzle.

*  Large Plastic Bucket

Chemicals & Oils

*   6 pounds of NaOH  (aka Sodium Hydroxide aka Caustic Soda aka Lye)  ++LINK++

*   3 pounds NaNO3 (aka Sodium Nitrate aka Nitrate of Soda)  ++LINK++

*   1 Package Na3PO4 (aka TSP aka Trisodium Phosphate) ++LINK++

*  Lots of White Vinegar

*  Acetone

*  H20 (hahah) –– Distilled Water.

*  WD40

*  Marvel Mystery Oil

*  Breakfree CLP

Other

*  Paper towels.

*  Goggles

*  Talc free rubber gloves.

*  Brushes (wire, and plastic)

*  OOOO Steel Wool

*   Cotton Rags (VERY IMPORTANT:  Make these from old T shirts, washed in the laundry with TSP and bleach –– NOT Tide or any other smell good detergent), and then dried WITHOUT any drier sheet.   These should smell like bleach and have no oil residue at all on them.  

*  White paper towels.   (The white is important).

CAUTION & DISCLAIMER
================

Alright.   Here's the disclaimer.   You will be working with LYE which is a nasty chemical, plus sodium nitrate (a moderately strong oxidizer), and all at very high heat.  

LYE is caustic, with a PH of 14.   Especially at the temperatures we're working with, it will break down human flesh at an astounding pace and turn your fat into soap.    It reacts suddenly and violently with everything from water, to aluminum, to sugar.   Those later two result in further dangers as hydrogen and carbon monoxide (respectively) are evolved from the reactions.  Here's what WIKI says about LYE:



I'll add that Norweigens also add it to fish to make Lutefisk (for goodness sake!)

My humor aside, This is is not a project to be approached lightly.  Aside from the Lye, you'll also be working with a fairly strong oxidizer (sodium nitrate –– close cousin to potassium nitrate of black powder fame), various oils and cleaners.    

Separation of work spaces is imperative.    Cleaners, oils, salts, etc.   All in different areas.   Don't let stuff mix that shouldn't mix.   You should do the bluing salts in your garage or on the deck.   Don't do it in the house.    Do not use ANYTHING made out of aluminum at any point in this process.   Not a pan, not foil, nothing.  

If you're the guy everyone knows by reputation as a klutz –– if you can't make dinner without spilling shit on the floor, if you drop things, if you can't keep out of your own way –– this is not the project for you.   It is extremely unforgiving.   You will mess yourself up.

EDITED TO ADD:   At the suggestion of a helpful commenter, I want to note that hot salts bluing (whether raw salts bluing, or caustic bluing with water as here) should not be used on soft solder projects.   If you have a front sight soft soldered in, its coming out and the solder will spoil the salts.   Keep that in mind.  

So, bottom line:    IF YOU TRY THIS STUFF, ITS AT YOUR OWN RISK.   BE CAREFUL.   I'M NOT RESPONSIBLE IF YOU MESS YOURSELF UP.


PROCEDURE
=========


STEP 1:  Leak check the tank.  

Take your brownells tank and fill it water.   Throw it on a burner on high inside the house and boil the heck out of it.   You want to be sure its not leaking water.  

STEP 2:   Get the Salts going.

GLOVES AND GOGGLES ON THIS STEP

Go outside:

Take 1/2 to 3/4 gallon of distilled water and put it on medium high heat.   Slowly stir in the 6 pounds of lye.    You will be amazed at how soluble it is.     The lye will make the water hot as it goes into solution.   Then add the Sodium Nitrate.   It can take an hour or more to get everything dissolved.  Put it on the burner and get the thermometer in there for a check.   You want to heat the salts up to between 265 to 308 degrees (f).   Too much hotter and it won't work.   Any cooler and the reaction either will not go, or will take a long time.   Personally, I actually tend toward the lower end... usually 275 to 290 degrees or so.

STEP 3:  Wire up the parts

Using black iron wire from Brownells, get your parts wired up so that they can be hung in the tank (not resting against the bottom or sides).  

From here on out, you'll be handling the parts only by the wire.  


STEP 4:   Degrease and clean

All metal work –– cutting, polishing, deburring –– should be done already.  

GLOVES AND GOGGLES ON THIS STEP

Working in a shallow glass basin, away from heat and flames, use acetone and a fine (acetone compatible) brush to clean oily residues from the parts.   Get in all the nooks and crannies.   Wipe off with clean cotton rags.  

Next, in a stainless steel pan, boil a couple gallons of regular water along with 1 table spoon of TSP.   It should be a thunderous roiling boil!    Dip the parts in this pan one at a time and boil for a few minutes.   The TSP is a strong degreaser and will get in the nooks and crannies.  

Take the parts to the sink and RINSE WELL with spray water.   Dry well with another clean T shirt rag while its still hot to avoid spotting.

Lay all the parts out (on clean T shirt rags))

STEP 5:   Preheat parts and into the tank

This step assumes your salts are all dissolved and between 275 and 308 degrees Fahrenheit.

GLOVES AND GOGGLES ON THIS STEP



Take the parts and dip them into DISTILLED water in another clean pan going at a rolling boil.  You're pre-heating the parts.   This step is optional with smaller parts, but some do it with the larger ones as I worry about warping with a shock of cold parts going right into the bluing salts.  NOTE:  Many people skip this step, and I have at times.   Its not a necessary step, but can't hurt unless you let too much water stay on the parts when they go into the much hotter salts, in which case you will mess yourself up.  

Now the moment of truth!

Take the parts out of the pre-heat, (or from your dry post-degreasing area if you're not preheating), make sure they're as dry as possible then lower into the salts and suspend appropriately.  

(AGAIN NOTE:  The salts raise the boiling point of the water they're dissolve in, so the "regular" water (if you leave any after preheating) will spatter and squirt and insta-boil when the parts go into the salt-bath.   If you're not wearing your gloves and goggles you'll regret it here. )

Keep stirring the solution around the parts, sort of "teabag" the parts in the salt, and keep a good circulation of salts in the bath.   DO NOT LET THE TEMPERATURE get too high.

Keep the parts in the salts for between 15 to 45 minutes.   Especially if you're pushing 300 degrees or more, too much longer than that and you'll have diminishing returns.

STEP 6:   Rinse and boil to remove salts.

GLOVES AND GOGGLES ON THIS STEP

Take the now VERY hot parts out of the salts, carry them in the house in a glass (NOT aluminum) casserole dish.    

Rinse in HOT water (it will steam and spatter because the steel parts will be hotter than the boiling point of watter) just enough to get most of the salts off, then dump them in a pan of boiling water.   Do this fast, and minimize the amount of time the parts are out in the open air.  Boil the parts a few minutes to try and get most of the salts out of the nooks and crannies.   The purpose of boiling the parts in water is to get salts out from nooks and crannies –– such as barrel threads, or under dovetails of the sights.     If you're bluing a simple part, you can skip the boil...  just use a spray rinse to really rinse it off.

STEP 7:   Oil Em Up

The next step will freak you out.     Don't worry about it.    Take another clean casserole dish and pull the parts out of the post-salts boiling water bath.   As soon as the parts touch "air" they will "flash" with a layer of red rust!   Don't worry, throw em in the casserole dish and spray liberally with WD 40.     Throw in some Marvel Mystery Oil, some 30 weight, whatever.   Just oil em up good and let them cool.  

STEP 8:  Unwire, polish and deflock

Once your parts are cooled down, you'll need to rub down, with rags, OOOO steel wool, and oil, each of the parts to give them a final polish and to get rid of a sort of reddish flock that develops on the outside of the parts in some areas.   You should not bear down too hard, or you'll remove the blue –– but this methodology really does get the finish pretty deep so don't worry too much.

I may be superstitious, but I like to throw the parts in tupperware with a mixture of WD40, Marvel, Breakfree and the like for a few days before reassembly.  


STEP 9:  CLEAN IT UP!

Ok,  once you remove the salts from the heat it will take HOURS for them to get back to a temp. where they're safe.   I just use a large plastic tupperware that is bigger than the tank to hold the whole thing once it is cool.

Use wet white paper towels to wipe down all the work areas.   Pay attention for yellow color appearing on the towels, as that is an indicator that Lye is there in strong concentration.   Use a spritzer bottle with vinegar to spray off all your surfaces, wipe down clean, etc.  





MY MOST RECENT PROJECT AND AN EXAMPLE OF HOW SALTS CAN GET KILLED
======================================================

This was a Finnish Luger pistol that I picked up for a few hundred dollars.  Why so cheap?

Because when it was imported, the importer dipped it in in a park tank without stripping the bluing.  The mixed finish mutt that resulted was so ugly the guy practically gave it away.

The gun had no collector value as a half blue half park mongrel, so I decided to make it a nice refinish project.

I employed the above procedure but had a major screw up which I'll use as a teachable moment.

See, here's what happened.   I blued the upper part of the Luger, and most of the small parts.    The bolt I had cleaned and degreased again because it did not get dark enough.   And I had just started the lower receiver.  

The disaster happened because I had been using a wooden stick, which you can see in the photos, from which to suspend the parts on their wires in the tank.   Well, as I was putting the bolt back in the salts with the lower, I bumped the stick and the end went in the salts.

There was an immediate reaction –– an off gassing that was super intense, and a 30 degree spike in the temperature of the salts right off the bat.  

Since I recognized that the a reaction was happening, I pulled the stick out and got out of the area.

When I pulled the parts from the salts, they were screwed up.   Reddish gold colored.   A test with some black iron wire (just sanded and dipped in) revealed the whole batch of salts got killed.   No more bluing happening.   Just this reddish / copper color.  

So what happened?   Treated wood.   The stick I was using was treated.   Usually copper / chromium compounds –– although I was distressed to see that arsenic is also mixed in with the old stuff.     When the wood dipped in the salts, i figure the most donative ion became all the copper that got into the salts.   My parts were taking on a thin layer of copper of all things.    So, I'll have to completely redo the bolt and the lower.   But everything else turned out well.  


PHOTOS
======

Here's the spread before getting started.


Here's the tank getting going.   My hotplate had enough stones and then some to keep it up to 300 degrees even with it fairly cold outside.


A picture of the Luger upper as it goes into the salts.


Here's how it looks while the salts are doing their thing.   Notice the piece of wood that wold ruin my day later.


Here's the upper coming out of the salts.   As soon as you pull them out the salts start crystallizing around the parts.


Here's a shot of my parts where they get sprayed by WD40.



My upper turned out pretty darned good.   Deep, dark, highly polished black.   Nice and even.



Here's a compare and contrast shot.   The toggle turned out good, but the bolt was in (I was trying to get it darker) at the time the contamination happened and its a "do over" now.


And a look at the frame.  What a freaking mess.   Actually, this finish would make a nice "browning" for old west style stuff.  But it is also a "do over.   Ugh.  




EDITED TO ADD:

Stripped (with dilute sulphuric acid) the copper cladding from the "ruined" salts from the lower AND from the metal tank which also had been coated (I did this outdoors and away from people in case there was indeed any arsenic in the wood preservative that poisoned the original batch of salts).  Then I  re-polished all the metal surfaces, cleaned and degreased, and fired up a new batch of salts.  

Success!

Side view (took this with a flash, so sorry about the glare)



Close up of left side.  When I was doing the metal prep, I used a checkering file to slightly touch up the mag release and takedown lever.


Top view.   Notice how much better the bolt looks now that the copper crud that screwed up my 1st batch of salts is off, and its been re-blued.  Notice, too, the extractor which was polished and then heat drawn to a nice "straw" color.


EDITED TO ADD:

More pictures from a prior project...  this one is a Star Model S in .380, nice Spanish steel.   I got this one as a rusted worn mess and decided to try my hand at checkering and refinishing.   This particuar pistol was refinished in a crock pot –– which just happened to have the right temperature range for hot bluing salts!   (Who knew!)...    I do recommend avoiding Crock Pot bluing, as the hot lye slowly dissolves the silica in the glaze in the earthenware pot, so it will eventually fail catastrophically.

Anyway, just some more pictures of how nice the home bluing can turn out.

thanks for taking the time to do this!!

TAG!!

This is good stuff.


Thank you.

You are a gentleman and a scholar.  Thanks for taking the time to put that on, I will definately be using it.  I was going to mention as far as your browser crashing.  Whenever I'm typing up anything sizeable on email or forums, I type it first in Microsoft Word (or works, etc) and save it as I go, then I can highlight the text, hit copy (ctrl - C), and paste it (ctrl - P) into AR15.com or en email.  This has saved my bacon many times when the post or send button didn't cooperate or my computer crashed.

Wow! Nicely done.  I love me some Lugar, turned out great.  So...ahh...what's the address to ship my worn Colt SAA to?

mfn

Bah!  

If your worn SAA Colt has its original finish and its not rusted or bubba-fied you may be better off leaving it original.

This method is for making "pretty" guns out of mongrels, mostly.

Sweet job, Gonzo!!!!  I am hoping that once we get the garage situmated that I can start playing with this too!!  I have two Reminton 22s that I did the wood on but still need to finish work the metal.

Awesome!  Be sure to take pictures and be safe with the chemicals.

Will do!  I have no desire to be dissolved by lye!!!  Ewww!!!

Nice job!


No need to preheat the parts. I've personally blued a lot of guns and seen many many more done and not a single one was pre-heated

I will be belgian blueing a revolver here in a few days


I didn't see if you mentioned it, but if you have any parts that are SOFT soldered on the salts will kill destroy that and they will fall off. Silver solder is fine.
I had to reblue a Winchester model 94 3 times because the FSB fell off the first time, then again after I re soldered it with low temp silver solder. Third time worked though.  


Be extra careful to get all the water off of the piece when you put it in the blueing tank, angle the barrel away from you or anything important. I have the burns to prove what happens when someone else puts a barrel in the tank with water still in it. Picture a steam powered lye cannon. I was not happy considering I had a running Ox-acetylene torch in my hand at the time.

Nice job and great write up

Thanks for the insight.   I'll go back in and add a note to the pre-heating section and some extra caution on the "no water" section.   I'll also add a section with some caution about brazed on sights or barrels.   I never even thought of that, but of course metals can melt and poison the salts too.   Thanks for the heads up!~

Belgian bluing is where you use boiled acid compounds and then card between applications sort  of like a rust blue, right?   Make sure you take pics and post a thread!

I will. Interesting story with it too. It was a sheriff's gun and he hid it inside a wall.After he died his son found, still loaded,  it rusted to hell, but the internals were still 100%. I couldn't remove all of the pits but did my best.

Neat story.   Just the kind of project these home re-blue situations work best on.

Midway sells a 40" tank for larger projects.  I've got an 1897 Winchester that would be a perfect candidate for some experimenting.  If it comes out nice I have a couple othersto throw in.  If/when I get around to it I'll postsome pictures.

How do you dispose of the chemical mixture?

The mixture is simply allowed to cool in place in the tank and put up, covered, for next time.    It should last for quite a long time.  The big gun makers have very large tanks and blue a lot of guns and then only change out the salts every year or half-year or so.   So don't get rid of the salts unless or until they quit working.

Beyond that, disposal of the salts is by and large a function of neutralizing the hydroxide.   Which takes quite a lot.   Previously, I have done some experimentation with this.  One  thing I've done is to take the salts from a pistol sized batch, pour them into a much larger quantity of water to seriously dilute the hydroxide, and then take a known volume (I used a standard lab flask 500ml I think) and titrate that dropwise with a known molar concentration of hydrochloric acid until you know how much of your concentration of HCl  needs to be added to neutralize.  Then extrapolate to what's in the bigger quantity.    What is happening here is that the OH- ions from the sodium hydroxide are combining with the H+ protons from the HCl (a monoprotic aocid) forming water (actually the acid has these exist as H3O+, the hydronium ion).  The surplus sodium and chlorine ions then make common salt.  You do it right and you are left with a solution with neutral acidity, with a quantity of dissolved sodium chloride and whatever is left of the Sodium Nitrate, some of which will be degraded to sodium nitrite by loss of oxygen atoms to iron oxide on the gun in the bluing process.     This resultant solution can be disposed in a drain in most areas, but check your local regs.    If you're really a chemistry jocky, you can evaporate the liquor to precipitate out the less soluble common salt, leaving a sodium nitrate/nitrite solution that can be used as fertilizer in some applications.

Of course, there's nothing wrong with pouring the (mostly cooled) used up bluing solution into a five gallon bucket, calling the local waste disposal folks and paying the fee to get rid of it.   In fact, that's probably what I'll have to do with the batch (still in my garage in a sealed bucket) that has the copper contamination.  

Very good question though:   Guys, don't do this if you can't or won't be responsible for proper disposal of your chemicals.  This is important, of course.

FWIW, there is an easier way to neutralize the lye solution.

Go to VWR or similar research supplier and purchase "universal range" pH indicating strips:

http://www.vwrsp.com/catalog/product/index.cgi?catalog_number=JT4397-1&inE=1&highlight=JT4397-1

Dilute the lye mixture in a large bucket with water. Slowly add muriatic acid (HCl-used for brick and mortar cleaning-you can buy it at any home improvement store) while stirring the mixture.  Follow the progress of neutralization with the strips until they indicate neutral pH.  Neutral is defined as pH 7, but anything from 5-8 is OK to put down the drain.  If you overshoot and make the solution too acidic, you can add more lye to bring the pH back up.

That came out incredible!



Nicely done on both the Luger and the bluing guide!

taggage

Gonzo, your work always looks fine.  Thanks!

This is amazing!

What was the total cost?  I'm looking at refinishing this Kimber and I'm not sire if its worth it for just one gun, or if I should just get it done by a pro.

Chemicals couldn't have cost more than $20 or $30 all told.

The quarter tank was the biggest cost.   Everything else I had hanging around already (including the @&#$#! treated wood that screwed up my first attempt).

For your gun consider this:

If you do your own metal work and prep, a lot of smiths will throw it in the tank for you for $100 or less.

If they bead blast only, standard price around here is $200 or so.

For a "factory" finish (which you may or may not be able to pull off yourself in terms of the metal work), some guys will ask for $300+

If it were my kimber, I'd probably do the metal work myself and enjoy the satisfaction of a job well done.

The biggest key with 1911 guns is that you have run the sides over a perfect flat, using high grade paper, and plate glass usually works best.   You should align the base of the slide against a plastic jig so that your polish marks are perfectly parallel.   I

Have you ever tried the bluing with a handgun that had a mirror finish polish on it?  I built a Caspian non A1 using Colt parts my Dad had years ago. I had everything polished to a mirror finish for a deep, high gloss blue finish and ready to send off to a bluer. But the guy told me that there had to be some "bite" to the finish for the bluing to "take" so I had him finish it with the standard bead blasted rounds and 400 grit on the flats. Still turned out beautiful, but it was not the high polish I really wanted.

I've seen mirror polishes get blued just fine. There are certain parts that you would not want polished that high though. The top of a 1911 for example, should be bead blasted IMO. If it isn't shooting in bright sunlight could be difficult. Less of an issue with blued compared to stainless I would think but either way that extra reflection or glare you can get off of it could mess with your sight picture.

I see what you are talking about, but honestly, it was going to be a B-B-Que gun with Ivorys. Dad opted out on the Ivorys and went with wood.

I'm not saying that is why he did that.

I would do my best to talk to the customer about it, explain why he might not want i that way, but in the end it is his gun and if he wants it high polish and blued that is what he gets. The problem is that if I don't do my job to educate the customer and just do exactly what he wants he may be unhappy with the results and blame the gunsmith, even though the work is good.

It could be he gave you a BS excuse because he can't work with that high a polish. I won't blue something that I haven't polished myself.

Don't worry about bluing salts, sodium hydroxide absorbs carbon dioxide from the air and it partly neutralized to sodium carbonate which is less harmful.  Mixing that with the liquid off of a  Damp Rid bucket (used to absorb humidity) turns that into calcium carbonate (limestone, active ingredient in Tums etc., chalk) and ordinary salt.



Yes, you COULD mix the spent bluing salts with Damp Rid solution (2NaOH + CaCl₂ = NaCl + Ca(OH)₂ with side reaction of Ca(OH)₂ + CO₂ = CaCO₃ + H₂O) BUT the energy of the reaction will cause  heating and could pose a danger.



Always best to run these neutralizing reactions slowly, meaning dilute.



Sodium nitrate is a fertilizer.